As a beginning point, it is useful to shortly describe the various forms of what is known in the industry as "resilient flooring" and to provide some background on the seaming techniques used in the past with that material. Resilient flooring is generic to:
linoleum;
rigid-backed vinyl (such as the material sold under the well known trade-mark CORLON);
cushion backed vinyl; and
homogeneous vinyl (which is a solid layer of vinyl).
Linoleum was commonly seamed by laying the vertical side edges of adjacent layers in close abutment, folding back the adjacent marginal portions of the floorcovering layers to expose the sub-floor, applying a band of water-resistant adhesive to the sub-floor along the line of abutment using a spatula-like tool called a `spreader`, then bringing the marginal portions back down onto the sub-floor, and hand-rolling the seam to complete the operation.
The rigid-backed vinyl was seamed in the same fashion as the linoleum, except that an excess of the sub-floor adhesive was applied to the sub-floor along the line of abutment, with the hope that it would squeeze up between the abutting side edges when they were pressed down, to seal and bond them together.
In the case of the cushion-backed vinyl, the marginal portions were first laid flat on the adhesive-coated sub-floor, in the same manner as linoleum. An applicator was then used to apply low viscosity, solvent-base, liquid adhesive into the closed seam. The applicator comprised a plastic squeeze bottle having a hollow, knife blade-like tip. The cushion-backed vinyl could be laterally compressed slightly, to allow penetration of the tip for application of the liquid adhesive.
In the case of the homogeneous vinyl, a narrow groove would be cut along the seam, a bead of vinyl would be laid into the groove and a hot iron would be used to melt the bead and adjacent material to thereby weld the side edges together.
From the foregoing, it will be understood that seaming involved bonding the undersurface of the floorcovering to the sub-floor with pre-applied thick adhesive and bonding the vertical side surfaces together, either by application of low viscosity, liquid adhesive or by heat welding the vinyl edges.
In the mid-eighties one of the present applicants developed a novel applicator tip for use with homogeneous vinyl. The tip was disclosed in U.S. Pat. No. 4,484,976, issued Nov. 27, 1985, and is hereafter referred to as the "prior tip".
This prior tip was designed to wet the vertical side edges of the floorcovering with a solvent-base liquid adhesive. The tip is adapted to raise the flat marginal portions of the floorcovering as it passes along the seam, thereby exposing the vertical side edges while wetting them with liquid adhesive. More particularly, the installer inserts the tip between the floorcovering side edges and beneath the adjacent marginal portions. He then pulls the tip along the seam. The tip is connected at its upper end to a plastic squeeze bottle containing a supply of liquid adhesive. The tip forms a longitudinal passageway having an outlet positioned to deliver the adhesive to the faces of the floorcovering side edges. The bottle is manually squeezed by the installer as he draws the assembly along the line of abutment, to discharge the adhesive.
Structurally, the prior tip comprises:
An upstanding, body having, from top to bottom, a leg portion, a relatively narrow ankle portion, and a relatively broad foot portion. The body is also formed with a notch projecting inwardly from its trailing edge, said notch being located at the juncture of the ankle and foot portions (since the body is pulled along the line of abutment or seam, it has leading and trailing edges);
The leg portion having coupling means at its upper end for connecting it with the adhesive supply squeeze bottle, as aforesaid;
A longitudinal open-ended passageway extending downwardly through the leg and ankle portions to an outlet located at the inner end of the notch, the outlet being positioned to discharge rearwardly;
The foot portion having downwardly and outwardly sloping flat upper surfaces extending laterally from a linear central apex to, in effect, provide a pair of side-by-side wedges having a common flat bottom surface; and
The foot portion further forming a longitudinal passageway which is an extension of the leg and ankle passageway, said foot passageway having a centrally located outlet in the foot portion's bottom surface.
In use, the prior tip involves the following:
The foot portion is inserted beneath the adjacent marginal portions of the two floorcovering layers. The wedges thus underlie the marginal portions and cause their side edges to be raised, tilted, spread apart and positioned in proximity to the sealant outlet and notch area; and
The combination of the notch walls and the upraised floorcovering side edges form a narrow chamber or conduit, open at the trailing end and having the adhesive outlet at its leading end--the adhesive is fed into the conduit, to wet the floorcovering side edges.
The prior tip has worked well when used with homogeneous vinyl using solvent-based liquid adhesive but, when applied to carpeting and other resilient flooring, certain problems have become evident. More particularly:
The ankle portion has had to be kept quite narrow (typically 1/16"). If this is not done, the seam will open too much as the tip is moved along it. An excessive amount of adhesive will then readily move down the conduit and into the open seam (this excessive flow is referred to as "flooding"). In the case of carpet, when the upraised marginal portions of the floorcovering drop back down to the sub-floor after the tip has passed, the excess adhesive will get squeezed upwardly and will wick into the pile. The installer can then attempt to clean off the surface adhesive, but this is time-consuming, expensive and rarely complete. The presence of adhesive on top of the seam will result in flattening of the pile fibers with traffic, thereby creating an undesired, hard, lumpy ridge running along the seam. In the case of resilient flooring, excess adhesive will accumulate on top of the finished seam and is wasted and must be removed;
Flooding is also partly a result of having to use low viscosity, solvent-based, liquid adhesive. These adhesives will readily flow down the passageway and through the outlet or orifice into the open seam. It has not been possible to substitute a high viscosity, water-based liquid adhesive (referred to hereinafter as "sealant") for use with the prior tip, as it will not flow at a sufficient rate through the narrow ankle passageway and orifice (which typically has a diameter of about 40/1000"). It would be desirable to use a high viscosity, water-based sealant, because it is less toxic than the solvent-based sealant. However this has been deterred because a passageway of greater cross-section would require a thicker ankle portion, which would result in opening the seam wider, thereby inducing an unacceptable degree of flooding;
In addition, it is desirable, with resilient flooring and carpet, to apply some of the sealant to the undersurface of the marginal portions of the floorcovering, to enhance the strength and durability of the seam. Attempts to accomplish this end with the prior tip, by delivering more sealant, simply result in more excess sealant reaching the top surface of the seam;
Since the sub-floor is normally coated with a tacky adhesive, when the prior tip is pressed down against the sub-floor and pulled along the seam the sub-floor adhesive will drag on the tip and will also ball up beneath it. This commonly causes the installer using the tip to lift it out of contact with the sub-floor during use. Several problems can then result. The floorcovering side edges can be spread too far apart, with the consequence that severe flooding will follow. Furthermore, the installer will have to manually press down the wetted edges as he proceeds. This means that the installer has to hold the bottle and tip with one hand, using that hand to squeeze the bottle, while he uses the other hand to press down the wetted side edges. All of this is tiring over time and requires a significant level of skill on the part of the installer. In addition, when the prior tip is lifted, it has a tendency to skew, with the result that the application of sealant to the two side edges is somewhat uneven and erratic;
As previously stated, it is desirable to apply beads of sealant to the undersurface of the floorcovering, both along the abutment line of the seam and laterally spaced therefrom. In the prior tip there is provided an internal passageway extension having an outlet in the bottom surface of the foot portion. However, it is found that there is insufficient pressure created in the passageway to consistently deliver sealant through this outlet for the purpose of wetting the undersurfaces;
When working with carpet, the pile tends to shield or hide the "work area" (where the outlet is discharging the sealant) from the view of the installer, making it difficult to know how hard to work the squeezing of the supply bottle; and
As a final point, the tip and attached bottle are unstable and tend to topple over if left in the seam.
It is therefore applicant's objective to modify the prior tip to overcome these problems and produce a better tip which can be used with floorcoverings such as carpet and resilient flooring and which is adapted to be used with high viscosity, water-based liquid adhesive (sealant).